Pathogenic microorganisms in water bodies pose health threats to wildlife and human beings. Disinfection of pathogenic microorganisms to eliminate their risks is an essential requirement of water/wastewater treatment. Photocatalytic disinfection driven by sunlight is a promising disinfection method, as it not only uses a green source of energy but also generates no toxic by-product. In this study, TiO₂-based photocatalysts have been developed for photocatalytic disinfection of sewage. The photocatalysts were further incorporated with superparamagnetic Fe₃O₄@SiO₂ to magnetize it, to allow their feasible separation from treated sewage.

The magnetic reusable Ag/Fe,N-TiO₂/Fe₃O₄@SiO₂ (AgFeNTFS) was developed via the sol-gel method, and then used for disinfection reaction in synthetic and aut...[ Read more ]

Pathogenic microorganisms in water bodies pose health threats to wildlife and human beings. Disinfection of pathogenic microorganisms to eliminate their risks is an essential requirement of water/wastewater treatment. Photocatalytic disinfection driven by sunlight is a promising disinfection method, as it not only uses a green source of energy but also generates no toxic by-product. In this study, TiO₂-based photocatalysts have been developed for photocatalytic disinfection of sewage. The photocatalysts were further incorporated with superparamagnetic Fe₃O₄@SiO₂ to magnetize it, to allow their feasible separation from treated sewage.

The magnetic reusable Ag/Fe,N-TiO₂/Fe₃O₄@SiO₂ (AgFeNTFS) was developed via the sol-gel method, and then used for disinfection reaction in synthetic and authentic sewage under visible light irradiation. The AgFeNTFS proved to be highly effective for disinfection of both synthetic and real sewage, and exhibited high magnetic separation efficiency and good reusability over three cycles for photocatalytic disinfection of E. coli. Also simultaneously achieved in the process was the degradation of bisphenol A (2 mg/L).

This study further developed the photocatalyst RGO/Fe,N-TiO₂/Fe₃O₄@SiO₂ (RGOFeNTFS) and examined its photocatalytic disinfection potential. Under simulated solar irradiation, RGOFeNTFS showed much potential for disinfection of real sewage, and no bacterial regrowth was observed in the treated sewage after 48 h. Both the RGOFeNTFS and treated sewage samples were also shown to be non-toxic, which was demonstrated via bioassay using natural-born phytoplankton in seawater as indicator. Several other coexisting bacteria were treated simultaneously in the photocatalytic disinfection, and were observed to respond differently to the photocatalytic disinfection as they interacted differently with the photocatalyst. The interactions between bacteria and RGOFeNTFS were analyzed in terms of Zeta potential, hydrophilicity and SEM. Moreover, the effects of water characteristics on photocatalytic disinfection efficiency were also examined to evaluate the practicality of photocatalytic disinfection of real sewage.